Surface active composition containing a corrosion inhibitor



Unite SURFACE ACTIVE COIWPOSITION CONTAINING A CORROSION INEHBITOR John F. Yost, Noroton Heights, Comm, assignor to American Cyanamid Company, New York, N. 1., a corporation of Maine No Drawing. Application December 2, 1953, Serial No. 395,855

6. Claims. or. 252-354 The present invention relates to new and improved surface-active compositions possessing anti-corrosive and anti-rusting characteristics and, more particularly, to surface-active compositions comprising esters of sulfodicarboxylic acids in aqueous media containing a corrosion inhibitor and possessing improved anti-corrosion and anti-rusting properties.

' Esters of sulfodicarboxylic acids have been known to the industry for a considerable period of time and their uses and applications are many and widespread. Reference is made to U. S. Patent No. 2,028,091, issued January 14, 1936, for a complete description of their methods of preparation and a list of their typical uses. When -used in aqueous media, these esters of sulfodicarboxylic acids have been found to improve the anti-corrosive prop- .erties thereof in many instances. However, in some cases where the requirements of particular circumstances are more exacting or the conditions of use are more drastic, such as when an extended storage period in an ordinary steel container is involved, or when the aqueous surface active agents are used with particular types of apparatus such as cotton gins, cotton pickers, fire fighting equipment, and so forth, corrosion and rusting has been found to occur.

It is, therefore, a principal object of the present in- Patented Apr. 9, 1957 to render them commercially unacceptable.

It is, therefore, another principal object to prepare a surface-active composition comprising a dialkyl sulfo suocinate in aqueous media and, as a corrosion inhibitor therefor, a compound which yields the desired anticorrosive and anti-rust properties, does not deteriorate on heating, does not possess any undesirable effect on the wetting power of the surface-active composition, is sufficiently compatible therewith and does not develop any undesirable acidity or basicity.

It has been found that such a corrosion inhibitor exists in the group of compounds consisting of N,N-dialkylsubstituted aniline in which the alkyl groups each contain from 1 to 5 carbon atoms. Illustrative, but not limitative, of such compounds are N,N-di1nethyl aniline, N,N-diethyl aniline, N,N-dipropyl aniline, N,N-diisopropyl aniline, N,N-dibutyl aniline, the N,N-diisobutyl anilines and the N,N-diamyl anilines.

Although the tests and experiments which will be set forth hereinafter employ dimethyl aniline as the illustrative inhibitor, it is to be pointed out that such is merely the preferred embodiment of the inventive concept and that such should not be construed as limitative thereof.

The effect of dimethyl aniline on aqueous solutions of sodium dioctyl sulfosuccinate, hereinafter sometimes referred to as OT, and on compositions comprising 85% sodium dioctyl sulfosuccinate and 15% sodium benzoate, hereinafter sometimes referred to as OTB, is set forth in Table I, along with the effect of other inhibitors on such solutions.

TABLE I Low carbon steel corrosion lnhlblIlOll-1% mhlbztor Corrosion Solution Inhibitor pH after 2 weeks 3 days 1 week 2 weeks Tap Water none serious serious serious G. 7 0T, 1% do some considerlo. 6. 6

OTB, 1% -do very slight. 6.9 0'1, ammontium carsome OT, 1%. very slight" 10. 4 OT, 1 none 9. 6 OT, 1% serious 6. 9 OT, 1% hydroquinone some 2 OT, 17 hydroxylamine-HCI... serious 6.2 OT, 1 phenyl urea 7. 2 OT, 1%. sodium nitrite 6.1 0'1, 1%. a-nitronaphthalerte. f3. 1 '1, 1%-. I hydrazine-H01 2. 9 OTB, 1% urea OTB, 1% NH HPO4 OT, 1% dlmethylaniliue- 7.0 GT3 1 .---.do o .do do 7.0

These tests, as well as the tests to be described hereinafter, were conducted as follows: The particular solutions were prepared and placed in test tubes and polished steel strips were immersed therein. These strips had been polished with fine emery paper and washed with water and acetone. No fingerprints were allowed to get on the strips. The test tubes were set aside and observed periodically, as indicated in the particular table.

A consideration of Table I indicates that a tap water solution resulted in serious corrosion within three days (actually, rusting occurred in less than 24 hours). The addition of OT 1% and OTB 1% improved the situation but corrosion took place in approximately one to two weeks. The use of several other inhibitors did not improve the situation in that corrosion took place relatively quickly and it is also to be noted that the pH wasiundesirably high or low. The use of dimethyl aniline, however, in OT 1% and OTB 1% prevented corrosion completely for the observed period and additionally maintained a desirable pH of 7.0.

Reference to Table Ii shows the eifect of various concentrations of dimethyl aniline on the rusting of OT in aqueous media in difierent concentrations. It is to be noted that the percent solids of dimethyl aniline is based on the percent solids of the surface-active agent rather than on the weight of the total sample.

TABLE II Rusting time EFFECT OF DIMEIHYL ANILINE N RUSTING O T Dimethy] State (Percent Aniline Rust Time, Days ids) (Percent Solids) 25.0 0. 0 M to 2. 24. 9 0. 2 7. 24. 9 O. 4 4. 24. 9 0. s so. 7 24. 8 0.8 N o Rust (70 days). 24. 8 1. 0 D0. 24. 6 1. Do 24. 5 2. 0 4. 24. 4 2. 5 M. 24. 2 3. 0 2. 23. 8 5. 0 2 22. 5 10. 0 2. 0. 02 0. 0 2. 0. 02 0. 0004 2. 0. O2 0. 0012 2. 0. 02 0. 002 2. 0. 02 0. 004 2. 1. 0 0. 0 2. 1. 0 0. 02 60. 1. 0 0. 06 70. l. 0 0. l 60. 1. 0 0. 2 No Rust (70 days).

surface-active agent and the formation of the dispersion or emulsion, the desired action was obtained.

In Table III is set forth the effect of dimethyl aniline V in 1% OTB on various metals. The percent solids of dimethyl aniline has been varied from very small to' very large amounts whereby desirable ranges for any particular material or use are clearly indicated.

TABLE III Two-week rusting test Dimethyl Corrosion Table noted the eflect of dimethyl aniline on 4 the wetting power of sodium dioctyl sulfosuccinate. The sinking time in seconds, of course, refers to the results of the standard Draves Test. The results are indicative of the fact that the wetting power of sodium dioctyl sulfosuccinate was not impaired by the addition of dimethyl aniline.

Additional testing indicated that dimethyl aniline was was compatible with sodium dioctyl sulfosuccinate in concentrations up to as high as 10%. Extended heating tests have indicated that dimethyl aniline in aqueous sodium dioctyl sulfosuccinate solution showed no deterioration in the stability of the sodium dioctyl sulfosuccinate.

The amount of the corrosion inhibitor present in the particular solution of the dialkyl sulfosuccinate will depend upon many factors, such as the concentration of the dialkyl sulfosuccinate, the nature and purpose of its intended use, the specific characteristics of the particular inhibitor employed, and so forth. It has been found, however, that in any event-the corrosion inhibitor must be present in an amount at least about 0.1% by weight of the dialkyl sulfosuccinate, as based on solids. The more common range for the amount of the corrosion inhibitor to be employed, however, has been found to fall within the range of from about 2% to about 6% by weight.

Although I have described several specific examples of my inventive concept and several results of tests thereon, I consider the invention not to be limited thereto, but that suitable changes, variations and modifications may be made without departing from the spirit and scope of the invention.

I claim:

1. A surface-active composition comprising anaqueous dispersion of a dialkyl sulfosuccinate and, as a corrosion inhibitor therefor, an N,N-dialkylaniline in which the alkyl groups each contain from one to 'five carbon atoms, said inhibitor being present in an amount of from 0.1% to 6% by weight of said dialkyl sulfosuccinate.

2. A composition according to claim 1 in which the inhibitor is N,N-dimethylaniline.

3. A composition according to claim 2 in which the N,N-dimethylaniline is present in an amount of from about 2% to about 6% by weight of said dialkyl sulfosuccinate.

4. A surface-active composition comprising an aqueous dispersion of dioctyl sodium sulfosuccinate and, as a corrosion inhibitor therefor, an N,N-dialky1aniline in which the alkyl groups each contain from one to five carbon atoms, said inhibitor being present in an amount of from 0.1% to 6% by weight of said dioctyl sodium sulfosuccinate.

5. A composition according to claim 4 in which the inhibitor is N,N-dimethy1aniline.

6. A composition according to claim 5 in which the N,N-dimethylaniline is present in an amount of from about 2% to about 6% by weight of said dioctyl sodium sulfosuccinate.

References Cited in the file of this patent UNITED STATES PATENTS 2,043,257 Missbach June 9, 1936 2,176,42 3 Jaeger Oct. 17, 1939 2,342,150 Kleinicke Feb. 22, 1944 2,618,608 Schaetfer Nov. 18, 1952 

1. A SURFACE-ACTIVE COMPOSITION COMPRISING AN AQUEOUS DISPERSION OF A DIALKYL SULFOSUCCINATE AND, AS A CORROSION INHIBITOR THEREFOR, AN N,N-DIALKYLANILINE IN WHICH THE ALKYL GROUPS EACH CONTAIN FROM ONE TO FIVE CARBON ATOMS, SAID INHIBITOR BEING PRESENT IN AN AMOUNT OF FROM 0.1% TO 6% BY WEIGHT OF SAID DIALKYL SULFOSUCCINATE. 